XRT83SH38 Datasheet, PDF (17/77 Pages) Exar Corporation – 8-CHANNEL T1/E1/J1 SHORT-HAUL LINE INTERFACE UNIT

XRT83SH38
REV. 1.0.3
8-CHANNEL T1/E1/J1 SHORT-HAUL LINE INTERFACE UNIT
ALARM FUNCTIONS/REDUNDANCY SUPPORT
SIGNAL NAME
GAUGE
DMO0
DMO1
DMO2
DMO3
DMO4
DMO5
DMO6
DMO7
RESET
SR/DR
RXTSEL
TXTSEL
BGA
LEAD #
J18
D5
D4
C15
C13
R5
P4
U17
V14
T8
K4
U11
V11
TYPE
DESCRIPTION
I Twisted Pair Cable Wire Gauge Select
Hardware Mode Only
This pin is used to match the frequency characteristics according to the gauge of
wire used in Telecom circuits. By default, the LIU is matched to 22 gauge or 24
gauge wire. To select 26 gauge, this pin must be pulled "High".
NOTE: Internally pulled “Low” with a 50kΩ resistor.
O Digital Monitor Output
When no transmit output pulse is detected for more than 128 TCLK cycles within the
transmit output buffer, the DMO pin will go "High" for a minimum of one TCLK cycle.
DMO will remain "High" until the transmitter sends a valid pulse.
NOTE: This pin can be used for redundancy applications to initiate an automatic
switch to a backup card.
I Hardware Reset Input
Active low signal. When this pin is pulled "Low" for more than 10µS, the internal reg-
isters are set to their default state. See the register description for the default val-
ues.
NOTE: Internally pulled "High" with a 50KΩ resistor.
I Single-Rail/Dual-Rail Data Format
Hardware Mode Only
This pin is used to control the data format on the facility side of the LIU to interface to
a Framer or Mapper/ASIC device. By default, dual rail mode is selected which relies
upon the Framer to handle the encoding/decoding functions. To select single rail
mode, this pin must be pulled "High". If single rail mode is selected, the LIU can
encode/decode AMI or B8ZS/HDB3 data formats.
NOTE: Internally pulled “Low” with a 50kΩ resistor.
I Receiver Termination Select
Hardware Mode
This pin is used to select between the internal and external impedance modes for
the receive path. By default, the receivers are configured for external impedance
mode, which is ideal for redundancy applications without relays. To select internal
impedance, this pin must be pulled "HIgh".
Host Mode
Internal/External impedance can be selected by programming the appropriate chan-
nel registers. However, to assist in redundancy applications, this pin can be used for
a hard switch if the RxTCNTL bit is set "High" in the appropriate global register. If
RxTCNTL is set "High", the individual RxTSEL register bits are ignored.
NOTE: This pin is internally pulled “Low” with a 50kΩ resistor.
I Transmitter Termination Select
Hardware Mode
This pin is used to select between the internal and external impedance modes for
the transmit path. By default, the receivers are configured for external impedance
mode, which is ideal for redundancy applications without relays. To select internal
impedance, this pin must be pulled "HIgh".
NOTE: This pin is internally pulled "Low".
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